Once cornered by a predator, prey can try to intimidate the assailant or repel it, with irritating sprays for example. If seized, they may scratch, bite or struggle to cause the predator to release its grip. At the other extreme, they can adopt passive behaviours such as death feigning (DF, i.e. thanatosis). DF is observed widely across the animal kingdom; it usually involves a combination of displays such as immobility, supination, leg‐folding, mouth opening and release of nauseating secretions. When displaying DF, individuals are highly vulnerable and effectively bet on the attitude of the predator; this risky choice is presumably under positive selection. We explored how propensity for DF varies among and within populations of dice snakes (Natrix tessellata). We also considered the influence of sex, body size, reproductive status, colour morph and presence of injuries (N = 2760 snakes; five populations). DF propensity differed among populations, possibly due to variation in local predation pressures. Larger snakes displayed DF more frequently and carried more signs of probable past predation attempts (scars and recent injuries). We found no sex effect on antipredator behaviour. Gravid females used DF less frequently compared with non‐gravid females. Differential expression of DF across populations, body sizes and reproductive status suggests that this complex behaviour was selected to respond to environmental and intrinsic factors. Future studies should explore which elements affect duration, intensity and success of DF in defence against various predators.

Pinna rudis (Linnaeus, 1758) or the rough pen shell, has Atlantic-Mediterranean distribution, and prefers warmer waters and harder substrates. Species is threatened by different factors and it is listed on Annex II of the Bern and Barcelona Convention. Some changes in species distribution are evident, most probably related to climate changes. Until 2018 presence of this species in the Adriatic Sea had not been confirmed with certainty, when it was find for the first time in Boka Kotorska Bay, what also presents first certain findings of the species in the Adriatic Sea. In this paper review on species presence along Mediterranean coast is given. Collected data indicate that species is more common in west Mediterranean compare to east and north part, and that future monitoring and status of population is required.

During the summer of 2013 two scientific surveys (northern, at the beginning of July and southern, at the end of July) were carried out along the eastern Adriatic Sea. In these surveys, ichthyoplankton samples of anchovy (Engraulis encrasicolus, Linnaeus 1758) eggs and larvae were collected. In the whole investigated area, egg and larvae abundance varied from 2.61 to 1040.24 eggs m−2 (geometric mean ± CL: 25.43 ± 1.48 eggs m−2) and 2.73 larvae m−2 to 611.14 larvae m−2 (geometric mean ± CL: 17.07 ± 1.41 larvae m−2), respectively. Higher abundance of anchovy early life stages was noted in the northern part of the investigated area. The length of the collected specimens lay within the range of 2.39–3.68 mm and those individuals were less than 12 h old. Analysis of spatial and temporal distribution of collected anchovy early life stages indicated their higher abundance in areas of upwelling (four areas were distinguished on the eastern Adriatic side). Larger and older specimens were collected at the beginning of July in the northern part of Adriatic indicating that the anchovy population in the Adriatic tends to shift among its spawning centres in this area. In general, anchovy eggs were accompanied by its larvae (r = 0.453, P < 0.05), while statistically significant negative correlation was obtained between egg abundance and temperature (r = −0.380, P < 0.05) as well as sea depth (r = −0.321, P < 0.05).

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This article present melanism in two species: Natrix natrix (Linnaeus, 1758) and Natrix tessellata (Laurenti, 1768) from Montenegro.